Outboard motor structure



.June 1, 1937.J F. T. IRGENs I OUTBOARD MOTOR STRUCTURE Filed Feb. 12, 1954 INVENTOR 00AM 7.' /MWM ATTORNEYS A Patented June 1,1937

UNITED STATES PATENTTT" OFFICE Outboard Motors Corporation,

Milwaukee,

Wis., a corporation of Michigan Application February 12, 1934, Serial No. 710,909

7 Claims.

This invention relates to improvements in outboard motor structures.

. It is the primary object of the invention to proff 'vide a marine propulsion device with an overload clutch between the engine and propeller and means effective upon the discontinuance of drive to the propeller to cut the engine speed, thereby preventing' it from racing and possible injury to itself and its operator.

The invention has particular application to an overload clutch of the type whichI is completely releasable upon the occurrence of overload. It has heretofore been proposed to incorporateaslip clutch in the drive to the propeller which would begin to slip when the propeller strikes asubmerged obstacle, thereby relieving the drivig connections of stress. In the present invention, however, a completely disengageable clutch is employed because of the fact that its release may be more accurately predetermined to occur at a specific amount of overload. Inasmuch as the clutch is completely selfdisengaging, I am able to avoid damage to the clutch and the propeller. It is generally true that if the propeller strikes one submerged obstacle it may either continue the engagement therewith or it may, as in the case of a rocky reef, encounter several additional obstacles. In the rst case a slip clutch would burn itself up, un-

less the motor is stopped or so reduced in speed that it will stop itself. In the second case, the release of the propeller from the first obstacle would enable it to regain speed immediately and it would encounter the additional obstacles at 5 high speed, thus injuring itself.

Regardless of what type of clutch is used, the present invention contemplates the closing of the engine throttle or other speed control; and when the clutch completely disengages itself, in accordance with the present disclosure, the full protection of the engine, driving connections, and propeller is assured.

The drawing illustrates a fragmentary side elevation of `an outboard motor embodying the invention, portions of the lower unit being shown in section.

The illustrated motor is merely an exemplification showing the application of the invention to one of many forms of marine propulsion devices.

By way of illustrating a means of controlling the engine speed, I have shown a carburetor I having a throttle lever 2 adjustable from a closed position represented by dotted line A, or to an idling position represented by dotted line B, or to an open position represented by dotted line C. A

pin 3 carried by the lever 2 is engageable in the slotted portion 4 of a control member 5 connected by means of Bowden wire 5a with the clutch which automatically permits the propeller 6 to come to rest while'the engine continues to op- 5 crate. With the control device 5 in the position shown in Fig. 1, the throttle lever is freely movable manually throughout its complete range of operation.. When the transmission of motion from the engine to the propeller is interrupted, 10 however, as hereinafter disclosed, or otherwise, the control device rises sufciently to bring the l throttle lever to its idling position as represented by the dotted line B, thereby preventing the engine from racing. 15

The engine power may reach the propeller through the conventional drive shaft 1, pinion 8,

bevel gear 9, and propeller shaft I0. In the present construction, however, the driven gear 9 is free to rotate upon the propeller shaft I0, 2o

being xed against axial displacement thereon by means of collars I I and I2. Within the broader purposes of the present invention any desired ltype of clutch automatically relieving the power shaft of motion may be employed to connect the 25 driven gear 9 with the propeller shaft. Specifically, however, for reasons above noted, it is desirable to use a clutch which completely disengages itself when a predetermined degree of overload is exceeded. 0

Clutch teeth I5 are formed on the rear face of the driven gear 9, and a clutch member I6 splined to the propeller shaft for axial movement thereon has complementary teeth at I'I. 'I'he pitch of the teeth is carefully determined with refer- 3- ence to the power to be transmitted and the range 1 of spring adjustment desired to determine the overload at which the clutch will operate A compression spring I8 seated against a collar I9 on the propeller shaft and exerting its thrust 40 upon the end of the clutch member I6 normally maintains the teeth II engaged with the teeth I5 to complete a driving connection between the gear 9 and the propeller shaft.

The clutch member IB'has a grooved or chan- 45 neled portion 20 in which is confined a clutch shifting collar 2| pivot-ally engaged by the shifting fork 22 and provided at 23 with an anti-friction thrust bearing functioning in the direction of a clutch engaging movement of the fork 22. 50 Fork 22 is pivoted at 2 4 and has a bell crank arm 25 comprising one link of a toggle lever. The other link 26 is connected to link 25 by means of a pintle at 21 and has its remote end loosely confined in a recess 28 in the lower unit or housing 55 29 of the outboard motor. From the pivot point at 24 a tension spring 30 leads to the free end of toggle link 26, and adjusting screw 3I threaded in a post 32 at the free end of link 25 has a swivel head 33 to which the spring 30 is connected. A removable plug 34 in the housing 29 gives access to the screw 3| for the adjustment thereof.

The Bowden wire sheath 35 is suitably anchored in the housing 29, and the wire 5a from the con'- trol member 5 is connected with the pintle 21 of the toggle lever in such a manner that the disengaging movement of the clutch element I5 will retard the throttle to reduce the engine to idling speeds.

The length of the shifting fork 22 and the disposition of the toggle lever is such that the tension spring 30 will exert little pressure through the shifting fork upon clutch element I6 in a direction to maintain the engagement of said clutch. Thus the anti-friction bearing 23 is relieved of load during the normal operation of the parts. If, however, the propeller strikes an obstacle and becomes overloaded, the pitch of the teeth I5 and I1 will cause clutch element I5 to separate from the gear 9 toward the disengaged position in which it is shown in the drawing.

When the clutch becomes partially disengaged, the movement of the shifting fork 22 will force the pintle 21 across the line of tension exerted by spring 3U, whereby such spring will begin to oppose spring I8 and will gradually overcome it, causing the retraction of clutch element I6 with a snap action to the position in which it is illustrated. 'I'he propeller will forthwith be relieved of all transmission of motion from the engine, the clutch parts will be completely disengaged and relieved of friction, and the engine will be protected by the movement of control device 5 to a position throttling the carburetor I. It is preferable that the engine lever be throttled instead of entirely cut off, in order to facilitate the reestablishment of a driving connection to the propeller.

As soon as the operator is satisfied that the propeller has cleared the obstacle or obstacles in its path, he then manually re-engages the clutch by manipulating the control device 5. Either concurrently or subsequently, he can re-establish the engine speed by manipulating the throttle lever 2, Thereupon the outboard motor will function like any conventional motor without the safety appliances herein disclosed.

I claim:

1. A marine propulsion device comprising the combination with an engine having speed control means, a propeller, and driving connections between said engine and propeller including an overload clutch having relatively movable parts, means controlled by the relative movement of said parts for effecting complete disengagement thereof, and motion transmitting connections from said means to said speed control device for regulating the rate of operation of the engine when said parts are disengaged.

2. In an outboard motor, the combination with a driving shaft and a propeller, of motion transmitting connections therebetween including an overload clutch having driving and driven parts completely separable automatically upon the occurrence of overload, a submersible housing wherein said parts are disposed, and means for resetting said clutch to effect the re-engagement of said parts, said means having a manually operable portion above the water level.

3. An outboard motor comprising the combination with an engine having speed control means, of a lower unit, an engine drive shaft leading to said lower suit, a. propeller shaft and propeller carried by said lower unit, gearing in said lower unit, and means comprising an overload clutch having completely disengageable parts normallyA engaged for the connection of said gearing and drive shaft in said lower unit,

together with a clutch resetting device having a manually operable portion above normal water level.

4. A marine propeller device comprising the combination with a propeller, a propeller shaft and a driving member concentric therewith, of a driven member slidable upon the propeller shaft, clutch teeth upon the respective members having a pitch such as to tend to separate said members under the infiuence of driving torque, and means effective upon the initial separation of said members to complete abruptly the separation thereof.

5. In a marine propeller device, the combination with an outboard motor including an engine, lower unit, propeller, and propeller driving shaft, of motion transmission connections in said lower unit including an overload clutch having completely separable parts, means tending to separate said parts upon the occurrence of overload, a snap action device connected with one of said parts and positively acting thereon in a direction to abruptly complete the separation initiated by overload between the parts, and a remote control mechanism for resetting said clutch including a manually operable portion above normal Water level.

6. In a marine propeller device, the combination with an outboard motor including an engine, lower unit, propeller, and propeller driving shaft, of motion transmission connections in said lower unit'l including an overload clutch having completely separable parts, means tending to separate said parts upon the occurrence of overload, a snap action device connected with one of said parts and positively acting thereon in a direction to abruptly complete the separation initiated by overload between the parts, and a remote control mechanism for resetting said clutch including a manually operable portion above normal water level, said engine having means controlling its operation connected with said portion for the actuation by said portion concurrently with the release of said clutch.

7. A device of the character described comprising the combination with a propeller and propeller shaft, of driving gearing including a gear concentric with said sha-ft and free to rotate thereon, clutch teeth upon said gear, a. gear element splined to said shaft and provided with complementary teeth, a clutch spring normally maintaining the teeth of said element and gear intermeshed, said teeth having a pitch tending under load to separate said element and gear against the compression of said spring, a snap action device connected with said element and provided with a spring operable following a predetermined separation of said teeth to oppose said first mentioned spring, whereby abruptly to complete the separation of said teeth, and means connected with said snap action device and with said element for manually re-engaging the teeth of said element with those of said gear.

FINN T. IRGENS. 

